Circuit controlling device



June 13, 1950 C, w, KUHN 2,511,640

CIRCUIT CONTROLLING DEVICE Filed Sept. 50, 1946 2 Sheets-Sheet l 6 l0 a5 a i la 4 67) I as* v MY, u 4

77 Z6 l -5l June 13, 1950 c. w. KUHN CIRCUIT coNTRoLLlNG DEVICE Filed sept. 3o, 194s 2 Sheets-Sheet 2 Patented June 1,3, 1950 CIRCUIT coNTRoLLING DEVICE Clarence W. Kuhn, Wauwato'sa, Wis., assigner to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application September 30, l1946, Serial No. 700,211

(Cl. 20o-83) Claims.

This invention relates to circuit controlling devices and is particularly applicable to autoe matic temperature controly switches for use in connection with electric refrigerators.

The invention has among its objects to provide an improved refrigerator control switch of the type including a front adjusting knob which is rotatable in opposite directionsy between given limits to eii'ect what is commonly known as cold control, and which operates in one of said limits to stop the refrigerator for defrosting Another object is to provide a compact, rugged reliable control switch of the aforesaid type which is exceedingly thin from front to back and is formed largely of sheet metal parts capable of being readily manufactured and assembled at low cost.

Another object is to provide a'refrig'erator ccntrol switch of the aforesaid type having improved temperature adjusting mechanism associated therewith. l

Various other objects and advantages of the invention will hereinafter appear.

'ihe accompanying drawings illustrate an embodiment of the invention which will now be described, it being understood that various modiiications may be made in the embodiment illustrated without departing from the spirit and scope of the appended claims.

In the drawings,

Figure i is a frontl elevational view of a switch embodying the invention, the adjusting knob therefor being shown in section;

Fig. 2 is a sectional view on line 2-2 of Fig.y l illustrating the switch in closed position;

Fig. 3 is a fragmentary sectional view taken substantially on line 3-3 of Fig. 1 illustrating the switch in circuit'opening position;

Fig. 4 is a sectional view on line 4-4 of Fig. 2;

Fig. 5 is an end elevationall view of the switch with a portion of the switch insulating base broken away and with a cover therefor removed; and

Fig. 6 is an exploded perspective View of certain of the parts shown inFigs. 1` and 2.

The refrigerator control switchv illustrated in the drawings includes a switch unit l and a unitary operating assembly therefor, including a snap operating mechanism 2 and a pressure re'- sponsive device 3. The snap operating mecha"- nism 2 and pressure responsive device 3 are mounted upon a rectangular base plate 4 and said pressure: responsive device has" a-"loading spring 51 asscciatedtherwith whichv isl adjustable by a' knob 6 through the medium of a screwy 'i an associated'nt 8. I

More speciiically, theY snap operating mechanisni 2"? is enclosed within a casing B; having an opening in one' end"Y thereofV for receiving the switch unitV l`. As illustrated? in Fi'gs l andu 2', base' plate 4; forms the' rear wall of said: casing 'and-'the other" walls thereof are formed by a front mounting plate i0 and a U-shaped sheet metal cover i which is located between said plates. Cover Ii is secured by riveting to forwardly extending projections l2-'I2 formed on opposite sides of an opening in base plate 4. Also cover il is secured to front plate l0 by projections I3 (Fig. which are formed on said plate and engage within openings inv cover Il.

The switch unit l includes an insulating base assembly i6 which carries a pair of stationary contacts lll-il and a cooperating bridging con-4 tact i5. Base assembly I6 comprises two molded insulatingv parts i9 and 2'0 which are secured together by a pair of rivets 2l. These insulating parts are formed to t within the end opening in casing and are secured therein by screws 2i." which extend through openings in front plate iii and thread into tapped openings in base plate li. insulating parts i9 and 2U are also formed to provide a contact-receiving recess 23 and a terminal receiving recess 24. As shown in Fig. 2, the stationary contacts il are clamped between the insulating parts I9l and 20 to hold the same in assembled position within recess 23 and each of said contacts is provided with a terminal portion 25 which extends into terminal recess 2:3 and is provided with a binding screw 2S. Bridging contact I8' is slidably supported within the recess 23 and is normally held in engagement with stationary contacts Il by a compression spring 2T. Said bridging contact has a pair of operating levers 2e associated with opposite ends thereof for moving the same into circuit opening position. As shown in Fig. 3, the operating levers extend inwardly beyond the base assembly It and each is fulcrumed at a point intermediate its ends uponv a knife edge bearing 2S formed upon the base part 20.

rihe snap operating mechanism 2 is of the typeY disclosed inthe patent to C. F. Robbins, No. 2,375,387, issued May 8, 1945. Said mechanism comprises an operating lever 30, a control lever 3l and a pair of over-center springs 32. As shown in Fig. 5, operating lever 3B comprises a rectangular sheet metal' stamping which is shaped to provide spaced side arms 33 and connecting end cross bars 3s and 35, and control lever Si also comprises a'sheet metal stamping which is shaped to provide spaced side rarms 3:'5 and connecting end cross bars 31 and 36. Also as shown in Fig. 6, the side projections l2-l2 on base plate' 44 are each formed to provide a pair of oppostely disposed V-shaped bearing notches 3Q and t5'. The side arms 33 of operating lever 3B are provided with ear projections 4i which engage within the bearing notches 39 and the side arms 3S of control lever 3l' are provided with ear projections 42 which engage within the bearing notches te. Operating lever 30 and control lever 3i are held in assembled position within their associated bearing notches by the overcenter springsv 32' and as shown in Figs. 3 and fi each of said springs has one end attached to end bar 35 of operating lever 30 and its opposite end attached to end bar 3l of control lever 3|. As shown in Fig. 2, the end bar 35 of operating lever 35 is disposed in front of the switch operating levers 25 and rotative movement of said operating lever in a clockwise direction is limited by engagement of said end bar with the head of an adjustable screw stop 43 carried by base plate 4. Also as shown in Fig. 2, control lever 3| is located to the rear of operating lever 38 and rotation of said lever in a counterclockwise direction is limited by inwardly extending stop projections 44 formed on the side arms l2 of base plate 4.

The operation of the aforedescribed snap operating mechanism is as follows. Normally the axes of springs 32 are located forwardly with respect to the bearing notches 39 and 45 so that control lever 3| is normally held in engagement with its associated stops 44 and operating lever 3|) is normally held in engagement with its associated screw stop 43. Upon a given degree of clockwise rotation of control lever 3| out of the position shown in Fig. 2 the axes of springs 32 are moved rearwardly across the bearing notches 39 and operating lever 3Q is then moved with a snap action from the position shown in Fig. 2 into vthe position shown in Fig. 3. Upon movement of operating lever 30 into the position shown in Fig. 3 the cross bar 35 thereof operates switch levers 2S for movement of bridging contact I8 into circuit opening position against the action of its associated spring 21. Rotation of control lever 3| in a clockwise direction (Fig. 3) is limited by engagement of said lever with the front surface of base plate 4 and upon movement of said control lever into said limit the axes of springs 32 are still located in front of the bearing notches 46. The over-center springs 32 thus act upon release of control lever 3| to return the same to the position shown in Fig. 2. Upon return of control lever 3| to the position shown in Fig. 2 the axes ofsprings 32 are moved forwardly across the bearing notches 39 to eect snap movement of operating lever 28 into the position shown in Fig. 2 for return of bridging contact I8 to circuit closing position under the action of spring 21.

Control lever 3| of the aforedescribed snap operating mechanism is operated by the pressure responsive device 3 and as shown in Fig. 2 said device includes a flexible metal diaphragm 45 'which is sealed within a rigid cup member 45 having a closed tube extension 41 connected to one side thereof. Diaphragm 45 is spaced with respect to the bottom wall of cup member 45 to provide a sealed chamber 48 and said chamber and the tube extension 41 are filled with a thermal responsive iiuid such as methyl chloride. The open end of cup member 45 is provided with an outwardly extending iiange of rectangular form and said flange is secured to the under side of base plate 4 by screws 49 which are illustrated by dotted lines in Fig. 1.

The loading spring associated with pressure responsive device 3 is of coil form and extends upwardly from diaphragm 45 through the opening in base plate 4 and through the openings in levers 30 and 3|. The rear end of loading spring 5 has a circular cup washer 5l) associated therewith which bears against the front face of diaphragm 45 and is operatively connected to the control lever 3| of the snap operating mechanism through the medium of a stirrup 5|. Cup

washer 50 and stirrup 5| are formed of sheet metal and said stirrup is interposed between said cup washer and the diaphragm 45 and is provided with forwardly extending arms 52 which are operatively connected to inwardly extending ears 53 (Fig. 6) formed on the side arms 36 of control lever 3|.

The above described switch may be used to control starting and stopping of an electric refrigerator and in such installations t Ie tube extension 4l is usually secured to the evaporator of the refrigerator so that the pressure of the uid in chamber 48 of pressure responsive de vice 3 varies in accordance with changes in ternperature of the evaporator. Thus upon warming of the evaporator the pressure of the fluid in chamber 4B will increase to effect expansion of diaphragm 45 against the action of loading spring 5. During expansive movement of diaphragm 45 stirrup 5| is maintained in engagement with washer 5D under the action of springs 32 and at a predetermined high temperature determined by the opposing force of loading spring 5 control lever 3| is moved by said springs into circuit closing position to eiect starting of the refrigerator. Upon starting of the refrigerator the pressure of the fluid in chamber 48 will decrease due to cooling of the evaporator and diaphragm 45 contracts under the action of loading spring 5. Upon contraction of diaphragm 45 the stirrup 5| moves therewith and upon a predetermined temperature drop control lever 3| is moved into circuit opening position to effect stopping of the refrigerator. As is apparent, variation of the degree of compression of loading spring 5 varies the temperature values at which the refrigerator is started and stopped. Also adjustment of screw stop 43 varies thev position of operating lever 30 to vary the point at which said lever is operated during movement of control lever 3B out of the position shown in Fig. 2. Adjustment of screw stop 43 therefore varies the degree of temperature drop which is required to effect stopping of the refrigerator.

As hereinbefore stated, loading spring 5 is adjustable by a knob 5 through the medium of a screw I and an associated nut 8. As shown in Fig. 2, nut 8 engages the front end of loading spring 5 and is movable axially within a forwardly extending cup projection 55 formed on front plate IB. Front plate Il] has a stop plate 55 welded to the rear face thereof, and as shown in Fig. 2 said stop plate is provided with a tongue projection 5l which engages within a slot 58 in nut 3 to hold said nut against rotative movement. 'Ihe front end of screw 'l abuts the front wall of cup projection 55, and as is apparent upon rotation of said screw nut 8 is adjusted axially to vary the degree of compression of loading spring 5. Screw 'l has an extension 59 formed on the front end thereof which extends through an opening in the front end of cup projection 55 and knob 6 is detachably and adjustably secured to said extension through the medium of a washer 65 and a coupling member 5|.

Washer 60 comprises a sheet metal stamping which is fixed to the front end of screw extension 59 and coupling member 6| also comprises a sheet metal stamping having a flat circular body portion 62 which is rotatablyV supported upon said screw extension. VAs shown in Figs. 1 and 2, the body portion 62 of coupling member 6| has a pair of rearwardly extending finger projections 63 and 64 formed on opposite sides thereof and said body portion is also shaped to provide shoulders l85 :on `opposite sides vof finger projection 64. Knob i6 is cup shaped to nt over the coupling member 6| and as :show-'n ln '-1 said knob iis detachably secured to said lcoupling lmemb'er by engagement of the Annger projections 6I and B4 within recesses 16B formed on the inner surface 'ofvsa'id knob. Also as shown l1in Eig.. v1, the inner surface of knob 6 lis shaped to provide projections 61 which-cooperate with the shoulders k85 toinsure that said knob is always mounted in -a :given angular position upon `coupling member El. As shown in dotted 'lines in Fig. 1, `the -body portion 562 of coupling` member r'6| provided with a slot 68 and washer "6U Lis provided with an indented 'portion 69 which engages within said slot to lock said coupling member in fa selected angular position with respect to screw '1.

Prior to locking of coupling member il to screw I said screw is shop adjusted for fa given normal setting of loading spring 15 and a line 4c-b (Fig. '"1) fis scribed -on the -face of washer fG 'in a direction correspond-ing to the normal setting of knob '6. Coupling member "6I "is v'then set in the position shown'in Fig. I so that the iinger projections G3 and l64 thereof yare alined with the scribed `line o-b and washer i60 is indented at 69 to lock said coupling member against rotation with respect to screw L As shown inFig. 6,one of the side arms 36 of lcontrol lever 3| is provided with an .arm 'T2 and as shown in Figs. 1 and 3 sani ar-m extends forwardly through a rvslot 13 formed in front pla-te l0. "Coupling member E-fl has a rearwardly 'extending iinger 1'4 Y'formed onone side thereof, and upon counterclockwise rotation of knob 56 Ainto a g-iven limit said linger is moved into engagement with arm 12 to move control lever 3l from Cthe `position shown inF-ig. 2 'into the position `shown in Fig. i3. Bridging contact i8 is ythus ymoved out of engagement withlits associated stationary 4contacts I1 to stop E'the refrigerator I'for defrosting thereof. As shown in Fig. f3, iront plate i is nprovided -with fa lforwardly lextending Astop -projection which is `:located at `one end of the slot T3. As lis apparent 'from Fig. 1,7 clockwise rotation fof vknob i6 is stopped lby Vdirect engagement'of iflnger '514 with one side of stop projection 15 and counterclockw'ise lrota-tion thereof 'is stopped Awhen arm 12 is fmoved 4by said'iinger into engagement with the y'opposite side of said stop projection.

-Switch unit 5I is -provided with `a removable insulating `cover plate '-16 having 'a `wiring Iopening 'I1 therein which communicates with the terminal `-recess'24 vin base assembly i5, As 4shown .in Fig. 2, the Iinsula-ting part of base Yassembly i6 'is Iprovided with a Vgrooved projection 1'8 `for rreceiving the -rearledge of cover plate I6 Yand said cover plate is held in assembled `position lwithin said groove yb y va vcatch I9 formed on the rear 'face of 'front plate l0. lThe left hand end of front plate 1l0-can 'be sprung forwardly to release `catch "19 from cover plate T6 and as is apparent said cover plate can .then be'remo'ved 'from the base assembly I'S.

What I claim as new and desire to secure by Letters Patent is:

v1. In combination, a thermal responsive switch mechanism having a helical loading 'spring vassociated therewith, a housing for said switch mechanism including a front mounting plate, said rloading spring beinglocated within said housing with Aits 'front end adjacent said vmounting plate and with its ax'is substantially perpendicular to the rear face of said plate, a non-rotatable adjusting nut engaging the front end of said spring, an adjusting screw supported within an opening in l'said lplate and rotatable to move said nut axially for variation of the loading effect .of said spring, :and a manual adjusting `mechanism associated with 'the front end :of said screw, said adjusting mechanism including a coupling Velement rotatably mounted upon :the Yfront end of said screw and having means associated therewith for securing the same in a .selected angular position with respect to said screw., and a manual adjusting knob detachably Ysecured to said screw by vengagement .of .said .coupling element within Aa .recess formed .in the .rear face of said knob.

2. 'In'combinatiom a thermal responsive switch mechanism having `a loading spring associated therewith, a housing for said .switch mechanism .including a front :mounting plate, said loading spring being vlocated within .said housing fand ,having an adjusting .screw associated therewith vwhich fis supported within :an opening in said mounting plate, .and a manual adjusting mechanism associated upon the ifront end `of said screw., .said manual adjusting mechanism includ-ing a coupling element rotatably mounted upon the front end of said screw and .having means .associated therewith A-for securing the :same in a selected :angular position with :respect to .said screw, and a manual adjusting knob Vde tachably secured to said screw through the medium of said coupling element said .coupling element having resilient parts Awhich engage within .a recess :formed in said knob.

3. In combination, :a thermal responsive switch mechanism 4having a :helical loading spring associated therewith, a housing for said switch :mechanism including .a Jfront .mounting iplate, a non-rotatable adjusting .nut `engaging :the iron-t end `of sa-id spring, .and -slidably supported `within a forwardly extending cup projection formed on isaid mounting plate, :an adjusting screw for said nu-t supported within an opening in the .iront end of .said Icup projection and rotatable to move fsaid nut axially for variation of the loading effect of said spring, :and a manual adjusting .mechanism .associated with the ffront end of .said screw, .said adjusting mechanism including a coupling member .rotatably mounted upon the front end of saidiscrew and having means associated therewith for securing :the same in a :selected angular position with respect to said screw, and a `manual adjusting knob secured Lto 4said screw through the medium of said coupling element, said adjusting -knob being .recessed to receive said kcup projection 4and :said ficoupling element having resilient parts which engage within said recess .to detachably hold said knob 2in :assembled position upon 'said screw..

4. Ina circuit controllingdevice, 'the combina- Vtion with la .housing open .at yone end and `including a V4iront mounting plate, a rear Ybase plate and la U-'shaped cover Lmember mounted between said plates, of :a unitary .control switch having an insulating support mounted within the -open `end of :said housing, a pressure responsive device .mounted upon said base plate and :hav-ing a loading .spring `associated therewith, a snap operating mechanism mounted within -said housing and operable by said pressure responsive device to effect vopening and closure of 'sa-id control switch, and 'an 'adjusting mechanism for said loading spring including a non-rotatable nut engaging said spring and slidably supported within a `forwardly extending cup projection formed in said mounting plate, an adjusting screw for said nut sulating support mounted within the open end of said housing, a pressure responsive device mounted upon said base plate and having a loading spring associated therewith, a snap operating mechanism mounted within said housing and operable by said pressure responsive device to effect opening and closure of said control switch, and a screw adjusting mechanism mounted upon said mounting plate for adjusting said loading spring to vary the pressure values at which said control switch is opened and closed by said device,

said screw adjusting mechanism being provided with a front adjusting knob and said snap operating mechanism having a part extending through an opening insaid mounting plate and operable by said adjusting knob to eiect opening and closure of said control switch.

6. In a circuit controlling device, the combination with a housing open at one end and including a front mounting plate, a rear base plate and a U-shaped cover member mounted between j said plates, of a unitary control switch having an insulating support mounted within the open end of said housing, a cover member associated with said insulating support and detachably held in position thereon through the medium of said front mounting plate, a pressure responsive device mounted upon said base plate and having a loading spring associated therewith, a snap operating mechanism mounted within said housing and operable by said pressure responsivedevice to eiect opening and closure of said control switch, and an adjusting mechanism for said loading spring including a screw extending into a forwardly extending cup projection formed in said plate and rotatably supported within an .a

opening in the front end of said cup projection, and an adjusting knob detachably secured to the front end of said screw and having a recess therein for receiving said cup projection.

7. In a thermal responsive switch mechanism.

the combination with an enclosing casing including a front mounting plate, of a thermal responsive switch operating mechanism mounted within said casing and having an associated loading spring of coil form extending forwardly toward said plate, a non-rotatable adjusting nut engaging the front end of said spring, said nut being supported within a forwardly extending cup projection formed in said plate to reduce the overall dimension of said enclosing casing rearwardly '1 of said plate, an adjusting screw for said nut rotatably supported within an opening in the front end of said cup projection, a coupling element mounted upon the front end of said screw and having means associated therewith for varying the angular position thereof with respect to said screw and an adjusting knob detachably secured to said screw through the medium of said coupling element, said knob being recessed to receive said coupling element and said coupling element having resilient parts associated therewith for engaging within said recess to detachably hold said knob in assembled position upon said screw. Y

8. In a circuit controlling device, the combination with a housing having an end opening and including a front mounting plate, a rear base plate and a U-shaped side wall mounted between said plates, of a unitary control switch having an insulating support mounted upon the open end of said housing, a pressure responsive device secured to said base plate and having an associated loading spring located within said housing, a snap operating mechanism mounted within said housing and operable by said pressure responsive device to effect opening and closure of said control switch, and an adjusting mechanism for said loading spring carried by said front mounting plate and including a rotatable adjusting part extending forwardly through an opening in said mounting plate and a manual adjusting knob detachably secured to the front end of said adjusting part.

9. In a circuit controlling device, the combination with a housing having an end opening and including a front mounting plate, a rear base plate and a U-shaped side wall mounted between said plates, of a unitary control switch including an insulating support having one end secured to the open end of said housing and having exposed terminal portions on the opposite end thereof, a terminal cover member associated with said insulating support and detachably held in assembled position thereon by latching engage- `ment with said front mounting plate, a pressure responsive device mounted upon said base plate and having a loading spring extending into said housing, a snap operating mechanism mounted within said housing and operable by said pressure responsive device to effect opening and closure of said control switch, and an adjusting mechanism for said loading spring including a rotatable adjusting part extending for'- wardly through an opening in said mounting plate and having a manual adjusting knob detachably secured to the front end thereof.

10. In a circuit controlling device, in combination, a housing having an end opening and comprising a yfront mounting plate, a rear base plate and a U-shaped side wall mounted between said plates, a unitary control switch including an insulating support mounted upon the open end of said housing, a pressure responsive device mounted upon said base plate and having a loading spring extending into said housing, a snap operating mechanism mounted within said housing and operable by said pressure responsive device to eifect opening and closure of said control switch, an adjusting mechanism for said loading spring including a manual adjusting member extending through an opening in said front mounting plate and rotatable in opposite directions between given extreme positions for adjustment of said loading spring, and means operable during nal movement of said adjusting member into one of its` extreme positions to eiTect operation of said snap operating mechanism for opening of said control switch.

CLARENCE W. KUHN.

The following references are of record in 'the ile oi' this patent: Y

UNITED STATES PATENTS Number Name Date v 2,179,599 Raney Nov. 14, 1939 2,276,885 Sherlock Mar. 17, 1942 

